James I-Sheng Huang1, Hui-Chieh Yu1, Yu-Chao Chang2. 1. School of Dentistry, Chung Shan Medical University, Taichung, Taiwan. 2. School of Dentistry, Chung Shan Medical University, Taichung, Taiwan; Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan. Electronic address: cyc@csmu.edu.tw.